THIS JUST IN!

In US cities, about 15 percent of land sits unused, vacant or abandoned. These spaces, which translate to an area the size of Switzerland, are associated with increased crime and stress to residents, especially in low-income neighborhoods. Plots of land with low-lying trees and shrubs, for instance, have been associated with a greater fear of crime, researchers wrote in the journal Proceedings of the National Academy of Sciences (PNAS), as the vegetation may hide potential attackers and illegal activity.

Vacant lots that have been cleaned up or “greened” seem to have the opposite effect and are linked with greater feelings of personal safety and lower levels of violence and crime.

Charles Branas, an epidemiologist at Columbia University, and colleagues decided to find out where vacant land restoration could have a citywide impact on crime and resident well-being, so they worked with the Pennsylvania Horticultural Society and Philadelphia Division of Housing and Community Development to clean up hundreds of vacant lots in Philadelphia.

The researchers specifically chose interventions that were inexpensive, scalable and sustainable, such that one day they could be applied to other US cities. The main intervention involved removing trash and debris from the lots, grading the land, planting grass and trees to create a park-like setting and installing a low wooden fence around the perimeter to signal that the lot was being cared for.